I'd genuinely like to see some objective information about the scene and how it qualifies as animal abuse. The AHA pretty closely monitors scenes with animals and has since the 1940s [1] albeit the rules and regs it follows have continually been improved upon. I understand that there are extenuating circumstances, like the tiger nearly drowning in the "Life of Pi," but from what I can tell, they mostly get it right. After looking for a good amount of time, I'm yet to find a substantiated account of how the rat in "Abyss" was subject to abuse. I understand how the scene might feel but feelings don't equate to actual events.
"The American Humane Association rated this film "unacceptable" because of the rat that was submerged in oxygenated liquid in one scene."
From the same page:
"James Cameron later admitted that four rats had indeed gone through the procedure without problems; the fifth, however, suffered a cardiac arrest. Fortunately, Cameron was able to revive it through careful chest compressions, and later kept it as a pet."
From the article linked in the original comment:
"Supposedly, the only purpose for the cuts in the sequence was to avoid showing the rats defecating from panic."
And you need only watch the scene to see a rat in enormous distress. I'm not sure what more you want.
[0] The first Google result is an explanation from American Humane themselves that they "were told there were no animals in the film. Therefore, AHA was not aware of the scene involving the rat and was not on the set."
[1] https://en.wikipedia.org/wiki/American_Humane#Work_in_the_fi...